N(1)-pentyl isatin-N(4)-methyl-N(4)-phenyl thiosemicarbazone (PITSc) as a corrosion inhibitor on mild steel in HCl

Abstract

A new isatin based thiosemicarbazone derivative [(Z)-N-methyl-2 (2-oxo-1-pentylindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (PITSc)] was examined as an inhibitor in acidic medium for mild steel corrosion. The inhibition efficiency of synthesized PITSc in 1 M HCl was assessed by means of weight loss method, potentiodynamic polarization and electrochemical impedance techniques. The Quantum chemical calculations were carried out by DFT method on the optimized structure of PITSc and its parameters were deliberated. The activation and thermodynamic parameters were calculated and discussed. PITSc obeys Langmuir adsorption isotherm on the metal surface in 1 M HCl. Single crystal X-ray crystallographic method was utilized to confirm the molecular structure of PITSc. The inhibition nature was discussed by several spectroscopic techniques like UV–Visible, FT-IR and by surface morphology methods such as SEM-EDS.